TB(P) Series Specification

Non-contact Infrared Temperature Sensor

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1.0.0

Typical application schematics

- TB series (External pull-up resistor required)

- TBP series(No external resistor required. 1.5㏀ pull-up resistor applied)

SMBus compatible 2-wire protocol

- The TB(P) series supports a 2 wire serial protocol. And the TB(P) only supports two

protocols on standard SMBus interface.

Supported commands are: Read Word, Write Word

Functional description

The TB(P) sensor module can only be used as a slave device. Maximum number of

devices on one bus is 127, higher pull-up currents are recommended for higher

number of devices, faster bus data transfer rates, and increased reactive loading of

the bus. If the access to the device is a read operation it will respond with 16 data

bits and 8 bit PEC only if its own slave address.

Bus Protocol

The TB(P) sensors are preset to address 0x3A by default.

1

7

1

1

8

1

1

S

Slave Address

Wr

A

Data Byte

A

P

S

Start Condition

Sr

Repeated Start Condition

Rd

Read (bit value of 1)

Wr

Write (bit value of 0)

A

Acknowledge(this bit can be 0 for ACK and 1 for Nack)

S

Stop condition

PEC

Packet Error Code(*)

Master-to-Slave

Slave-to-Master

* The PEC calculation includes all bits except the START, REPEATED START, STOP, ACK,

and NACK bits. The PEC is a CRC-8 with polynomial X8+X2+X1+1. The MSB(Most

Significant Bit) of every byte is transferred first.

Packet Error Code(PEC) Calculation

A packet error checking mechanism according to SMBus specification version 1.1 is

implemented. The packet error checking of SMBus devices uses an 8-bit cyclic

redundancy check (CRC-8) to calculate the PEC.

The polynomial used is C(x)= 100000111 (= x8 + x2 + x + 1) .

The PEC calculation includes all bytes in the transmission, including address,

command and data. It does not include ACK, NACK, START, STOP bits. Refer to the

Arduino example code for detailed PEC calculation.

Read Word

1

7

1

1

8

1

1

7

1

1

S

Slave Address

Wr

A

Command

Address(*)

A

Sr

Slave

Address

Rd

A

8

1

8

1

8

1

1

∙∙∙

Data Byte

Low

A

Data Byte

High

A

PEC

A

P

* Command Address configures

Register Name

Command Address

R/W

Ambient

0x06

R

Object

0x07

R

Emissivity correction coefficient

0x24

R/W

Slave Address

0x2E

R/W

Any device will respond to address zero

The MSB of the temperature data is an error flag (active high).

Please note after POR additional delay is needed before first reading can be started.

- Read operation flow diagram

Oscilloscope waveform image 1. (Read Object)

Oscilloscope waveform image 2. (Read Ambient)